Various types of tank systems are available for the transportation and storage of ultra cold liquids, for example, liquefied natural gas (LNG). Non-self-supporting membrane tanks, in which the containment system is installed directly on the load-bearing structure, represent a variant that is widely used because of the large cargo volume.
Membrane tank systems are made, corresponding to applicable sets of rules, e.g., the IGC Code, of at least one gas-tight barrier layer and at least one insulating layer; two gas-tight barrier layers are required in the example of the IGC code.
Shrinkage of the barrier material occurs due to the very low temperatures of the cargo being transported, which are, for example, −160° C. and lower. Since the tank system is rigidly connected to the load-bearing structure, these shrinkages are to be compensated by compensating elements.
Membrane tank systems being used currently use metallic materials as a barrier material and compensate the shrinkages by introducing compensators in the form of beads. The use of special alloys, for example, FeNi36, whose coefficient of thermal expansion is very low, is also known for minimizing shrinkages.
Based on the isotropic material characteristics (materials geometrically uniformly expanding or contracting during temperature changes), compensating beads are necessary in a plurality of directions, which inevitably causes beads to geometrically intersect each other. This requires crossing elements of complex shapes or the interruption of a bead, which leads to stress peaks in the barrier.
A multilayer panel for lining liquefied-gas containers with an insulating plate consisting of a heat-insulating material and a seal coating, in which the seal coating has a thermal compensator designed as an endless, e.g., circular bead, is known from WO 2008/125248.